Process of preparing 1, 4, 5, 8-naphthalene-tetra-carboxylic acid and substitution product thereof



I Patented Aug. 20,1935

UNI'TE'Dfi-STATE5? PROCESS OF PREPARING 1,4,5,z;axmrnirnav LENE TETRA CARBOXYLIC ACID AND sons'rrrurron PRODUCT THEREOF Wilhelm Eckert, Heinrich 1Sieber,r and ,Heinrich Greune, Frankfort-on-the-MainrHochst,. and

Gerhard Langbein, Hoflieim 'in "Taunus, Germany, assignors to General Aniline Works, Inc.,

.New York, N. Y., a corporation of Delaware No Drawing. Application August 27, 1930, Serial No. 478,312. In Germany- September 28,1929

The present invention relates to a process of preparing 1,4,5,8 -'naphthalene tetra-carboxylic acid and substitution products thereof. 'We have found that 1,4,5, 8-napl1thalene-tetrat carboxylic acid and substitution products thereof may be obtained in good yields by treating with an oxidizing agent a cyclic ketone of acenaphthene or a derivative thereof of the general probable formula:

' may be subjected to the oxidation. They are to bec n idered as quivalent tarn material and e r witni thesco eof the fdllofvvin'g claimsg 1 derivatives used as startingmaterials are obtain able by treating, the condensation products, obtainable from 'cyanoacetylchloride"and acenaphthene or its derivatives, of the following constitution: V o

' Hugeug,

with condensing agents as for instance-aluminium V chloride, aluminium chloride vmixed with-394112501 the'like (c mpare U; s. Patents 1,972,219 and 1,913,798). The cyclic ketones have the following constitution 11:

' c 1 n 'c cm no'oc coon wherein the naphthalene nucleus may be substie tutedornot; They are transformedinto the corresponding naphthalene-tetra-carboxylic acid as represented.-

in the above formula III by-I'neans of oxidizing agents. The1,4,533-naphthalene-tetra-carboxylic acid or its. derivatives, obtainable according to the said 'process in' good yield, represent intermediate 7 products of value for-the'preparation of dyestuffs. The following examples illustrate the invention, but they are not intended to limit itthereto, the

parts being by weight:

,(1) 44 mm ofv cyclic ketone of-"tlie acenaphthene in the form of its hydrochloride of the" probable formula: I

' HzC|l-(|3H2 or thelcorresponding quantity of the free ketone (obtainableaccording to U. S. Patent No. 1,913,798,

dated June 13, 1933) are suspended in about 1000 parts of caustic soda solution of 4 percent strength and the whole is heated' up to C.- C. About parts of potassium permanganate in the form of a warm aqueous solution of 10 per cent strength 7 are added to this mixture little by little until no further separation of p'yrolusite takes place. The

pyrolusite is filtered with suction and the 1,458-

naphthalene-tetra-carboxylic acid thus formed is precipitated in the filtrate by means of concentrated hydrochloric acid, filtered with suction,

Washed until neutral and dried. After the filtrate has been allowed to stand for a prolonged'time further quantities of the acid can be obtained,

therefrom.

(2) parts of cyclic'ketone of the acenaphthene in the form of its hydrochloride 'as used in Example 1 or the corresponding quantity of the free ketone are dissolved in 50 parts of concentratedsulfuric acid of 95 per cent strength and, the

solution is poured on 200 parts of ice. 25.1mm of sodium bichromate aregradually entered at a temperature of 50 C. The temperature is kept for 2 hours at 50 C. and then forabout? hours at 70 C. The 1,4,5,8-naphthalene-tetra-carboxylicx acid thus formed is filtered with suction, washed until neutral anddried. M U

(3) parts of cyclic ketone of the acenaphthene in the form of its hydrochloride (as referred p to in the preceding examples) are suspendedin 120 parts by volume of caustic soda solutionof 10 percent strength. 150-200 parts by volume of a commercial chloride of lime" liquor are then graduallyadded drop by drop at room temperature and the whole is heated for about 9 hours at 80"- whencareiully heated to anelevated temperature,

is transformed with elimination of water into the di-anhydride'. The-s'aid'acid isvery resistant; it can for instance berecrystallized from nitricacid whereby it is likewise convertedinto its yellowish di-anhydride. The yield of Lida-naphthalenetetra-carboxylic acid is satisfactoryi; T (4) 8 parts of ketimide hydrochloride 1 of 2- chloro-acenaphth-peri-indandion of the following are finely dispersed-in a solution of 32 parts of sodium bichromate in 200 parts of water.

suspension drop by drop at a temperature of 50? C., while well stirring. At 55 C.-60 C. stirring is continued until the oxidation is complete.

2- chloro- 1,4,5,8 naphthalene-tetra carboxylic The acid thusobtained of the'following constitution:

' 1100 loon 7' colorless solution. The

112 parts of sulfuric acid of.60 Brare added to the' is filtered with suction, washed until neutral and dried. It represents as free acid a nearly white powder which is soluble in alkalies and which can be precipitated again by means of acids. "The 2- chloro-1,4,5,8-naphthalenetetra-carboxylic acid crystallizes in the form of clustered prisms and melts at above 300 C. On heated up to an elevated temperature it is transformed while assuming a yellow coloration into its di-anhydride of the following constitution:

It dissolves in concentrated sulfuric acid to a yield is satisfactory.

1 We claim;

.1 The; process which. comprises subjecting a compound of thefcllowi'ng formula: V.

wherein the naphthalene nucleus may contain chlorine as a substituent to the action of a strong oxidizing agent in the presence of a diluent.

' 2. The process which comprises subjecting a 'compoundof the following formula:

wherein. cheer the Xs for hydrogen, the

other'X for'hydrogen or chlorine, to the action of uuggntjf .3. The'proce'ss. which comprises subjecting a compoundof thefollowing formula;

a strongoxidizing'.agent .in .the presence. of a wherein one of the Xs stands for hydrogen, the other X for-hydrogen or chlorine, to the action of a strong oxidizing agent; in thepresence of a diluent at a temperatureibetween' 50 .C.-110 C.

4. The process which comprises subjecting a compound of the following formula:

EEC-PHI HN= C 0 wherein one of the Xs stands for hydrogen, the other X for hydrogen or chlorine to the action of sodium bichromate in the presence of sulfuric acid at about C. to about C.

5. The process which comprises subjecting, a compound of the following formula:

to the action of potassium permanganate in the c to the action of sodium hypochlorite in the presence. of an aqueous solution of caustic soda at about C.

.7. Z-chloro 1,4,5,8 naphthalene e tetra carboxylic acid being a nearly white powder soluble in caustic alkalies, crystallizing in the-form of prisms, melting above 300 C. and. dissolving in concentrated sulfuric acid to a colorless solution.

WILHELM ECKERT. HEINRICH SIEBER. HEINRICH GREUNE. GERHARD LANGBEIN. 

